A modified Luxol fast blue technique was used to study the development of the temporal bone. This staining method makes it possible to make a clear distinction between the primitive cartilage present and the new forming bone. Although these tissues both contain a significant amount of collagen, their staining properties with the Luxol dyes are widely dissimilar, due to the different physicochemical properties of the collagen types involved in these tissues. The differentiation of mesenchymatous tissue into ligaments and joints can also be very clearly demonstrated with this technique. In studying the endochondral ossification process of the otic capsule and middle ear, the modified Luxol fast blue stain is a valuable technique that is complementary to more conventional staining methods.